brake booster question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**vetnat** · 09-13-2018, 01:38 AM

Hi, normally post over in 60-66 section. I have installed a booster from a 97 full size truck into my 1961. Pulled it off a truck at the junk yard. Chose this particular booster because master cylinder was already off, making my job easier. I have a weird question, I am wondering if anyone has removed/adjusted the booster push rod, and if so, how it is done. I have a sinking feeling that the push rod was actually missing off the one I grabbed, but since my truck originally had manual brakes, I had nothing to compare to. To be clear, I'm not talking about the rod that goes to the brake pedal, but the rod between the booster and the master cylinder. Of course, I already have the master cylinder installed and the lines filled and bled, but I am in the process of adapting the linkage to the brake pedal. I used a vacuum bleeder since I don't have the pedal hooked up yet. So, I am planning to go back to the junk yard after work tomorrow, and see if I can get just the booster push rod, in case my suspicions are correct, and mine is actually missing. I actually pulled this booster last summer, and would like to use it if at all possible, since I already have it installed , and I remember how unpleasant removing the nuts from inside the cab under the dash was. Yes, fools rush in. Has anybody done anything with the booster push rod? I found one video online, where the pushrod appeared to fall out when the guy was removing the master cylinder. Thanks for any help.

**Mr_Rich** · 09-13-2018, 03:45 AM

In my experience the pushrod for the manual master cyl. is shorter than the one for the power brake master cyl. The hole on the master cyl. piston is deeper on the power brake master cyl. so you need a longer pushrod for that one. Has anyone experienced something different?

mikebte · 09-13-2018, 10:38 AM

Visually out can look in the booster and see the push rod and the tip should have an adjusting tip on it. The rod only has a small amount of adjustment, but you could run it out till you feel the master cylinder touch it, than run it back in and check operation. If its missing you can make one.

If its to far out your brakes will be applied, to far in and you will have pedal travel and weak brakes. Hope this helps

**vetnat** · 09-13-2018, 04:53 PM

Thanks for the replies. That's a great picture. Are they threaded into the booster, or pressed in or bonded in somehow? Will try removing a push rod at the junk yard tonight.

**vetnat** · 09-17-2018, 01:34 AM

All right. Got the push rod at the junkyard on Saturday, since they closed 2 hours before their posted time on Thursday. That was a waste of leaving work half hour early. The push rod just sits in the booster, I pulled it out with my finger tips. Guess that explains why I was missing it, likely fell out somewhere during transport or storage of the booster. It is exactly 2.5" long, and about .36" diameter, with the bottom tip about .30" Also removed a nice split bench seat, tan colour.

**Palf70Step** · 09-17-2018, 07:36 AM

Glad you found one and the seat

09-13-2018, 01:38 AM	#1
vetnat Senior Member Join Date: Jun 2015 Location: Moose Jaw, SK Posts: 510	brake booster question Hi, normally post over in 60-66 section. I have installed a booster from a 97 full size truck into my 1961. Pulled it off a truck at the junk yard. Chose this particular booster because master cylinder was already off, making my job easier. I have a weird question, I am wondering if anyone has removed/adjusted the booster push rod, and if so, how it is done. I have a sinking feeling that the push rod was actually missing off the one I grabbed, but since my truck originally had manual brakes, I had nothing to compare to. To be clear, I'm not talking about the rod that goes to the brake pedal, but the rod between the booster and the master cylinder. Of course, I already have the master cylinder installed and the lines filled and bled, but I am in the process of adapting the linkage to the brake pedal. I used a vacuum bleeder since I don't have the pedal hooked up yet. So, I am planning to go back to the junk yard after work tomorrow, and see if I can get just the booster push rod, in case my suspicions are correct, and mine is actually missing. I actually pulled this booster last summer, and would like to use it if at all possible, since I already have it installed , and I remember how unpleasant removing the nuts from inside the cab under the dash was. Yes, fools rush in. Has anybody done anything with the booster push rod? I found one video online, where the pushrod appeared to fall out when the guy was removing the master cylinder. Thanks for any help. __________________ 1961 GMC half ton, short step, Canadian model. Just starting work on it. Last edited by vetnat; 09-13-2018 at 01:40 AM. Reason: clarity

09-13-2018, 03:45 AM	#2
Mr_Rich Registered User Join Date: May 2006 Location: Santa Maria, Calif. Posts: 781	Re: brake booster question In my experience the pushrod for the manual master cyl. is shorter than the one for the power brake master cyl. The hole on the master cyl. piston is deeper on the power brake master cyl. so you need a longer pushrod for that one. Has anyone experienced something different? __________________ 1989 K1500 Chev. EC Original owner; some of the aftermarket parts I've installed are Borla headers, Hypertech chip, Edelbrock water pump, and a Stillen rear disc brake conversion kit. 2009 Hummer H3T 3.7L 5M (sold) 1997 K2500 Chev. EC 7.4L/ 4L80E 2018 Dodge Ram 2500 HD R/C

09-13-2018, 10:38 AM	#3
mikebte Registered User Join Date: Oct 2011 Location: Tucson, AZ Posts: 639	Re: brake booster question Visually out can look in the booster and see the push rod and the tip should have an adjusting tip on it. The rod only has a small amount of adjustment, but you could run it out till you feel the master cylinder touch it, than run it back in and check operation. If its missing you can make one. If its to far out your brakes will be applied, to far in and you will have pedal travel and weak brakes. Hope this helps Attached Images __________________ 1959 Chevy Apache 3100/ 283 TBI / 4L60E My YouTube: https://www.youtube.com/mikebtte

09-13-2018, 04:53 PM	#4
vetnat Senior Member Join Date: Jun 2015 Location: Moose Jaw, SK Posts: 510	Re: brake booster question Thanks for the replies. That's a great picture. Are they threaded into the booster, or pressed in or bonded in somehow? Will try removing a push rod at the junk yard tonight. __________________ 1961 GMC half ton, short step, Canadian model. Just starting work on it.

09-17-2018, 01:34 AM	#5
vetnat Senior Member Join Date: Jun 2015 Location: Moose Jaw, SK Posts: 510	Re: brake booster question All right. Got the push rod at the junkyard on Saturday, since they closed 2 hours before their posted time on Thursday. That was a waste of leaving work half hour early. The push rod just sits in the booster, I pulled it out with my finger tips. Guess that explains why I was missing it, likely fell out somewhere during transport or storage of the booster. It is exactly 2.5" long, and about .36" diameter, with the bottom tip about .30" Also removed a nice split bench seat, tan colour. Attached Images __________________ 1961 GMC half ton, short step, Canadian model. Just starting work on it.

09-17-2018, 07:36 AM	#6
Palf70Step State of Confusion! Join Date: Jul 2002 Location: Gulfport, MS USA Posts: 46,611	Re: brake booster question Glad you found one and the seat __________________ Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God!



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.